DL-Cystine

L-cystine D-cystine DL-cystine metbionine [56-893] [349-46-2] [923-32-0] [7005-18-7 J Met 2-arnino-4-rnetbyl-tbi obutanoic acid CH3SCH2CH2 CHCOOH 149.21... 

Sodium selenite and selenodiglutathione have been found to be more effective in inhibiting the growth of Ehrlich ascites tumors than sodium selenide, dimethyl selenide or seleno-DL-cystine. Preincubation of tumor cells with either 1 or 3 ppm Se as GSSeSG, Na SeO or dimethylselenide before reinoculated into mice resulted in a significant increase in survival in mice inoculated with cells pretreated with GSSeSG (69) (Table IV). Vernie et al.,... 

M. R. Da Silva, R. M. Olivas, O. F. X. Donard, M. Lamotte, Determination of the deprotonation constants of seleno-DL-cystine and seleno-DL-methionine and implication to their separation by HPLC, Appl. Organomet. Chem., 11 (1997), 21-30. 

Decomp 260-261°. d-Cystine Crystals. Sidy sol in water. dl-Cystine, the synthetic racemic form Crystals. Sltly sol in water. meso-Cystine, the internally compensated form Crystals. Sltly sol in water. 

Benzyl mercaptan added to a soln. of Na in anhydrous ethanol, the resulting soln. added to crude ethyl piperidinomethylacetaminomalonate methiodide in 3 decreasing portions and refluxed 5 hrs. after each addition -> ethyl 3-benzyl-thio-2-acetaminopropionate. Y 71%. Also with labeled compounds as one step in a synthesis of DL-cystine- G-3 s. G. M. Gasparini, L. Pichat, and C. Baret, Bl. 1965, 794. 

Other polypeptide networks, for example based on 1-glutamic acid and dl-cystine residues contracted in their isoelectric region and extended in both acidic and basic media. 

H. Yuki and his coworkers synthesized three-dimensional polypeptide networks composed of 1-glutamic acid and dl-cystine residues, and their reversible contractility upon changes in pH and ionic strength was studied. A foil made of this polypeptide contracted in its isoelectric region and extended in both acidic and basic media. 

In a little known work, Palaszek examined the conversion of several simple " C-labelled precursors into a-terthienyl in T, erecta 196). These were DL-glucose-UL- C, DL-ornithine-2- C, sodium malonate-2- C, DL-cystine-l- C, DL-serine-3- C, malonic-2- C acid, DL-methionine-2- C, and sodium pimelate-T- C. The dilution factors for the last three were the lowest, 1865, 1385 and 445 respectively. Thus preformed polyacetylenes are not necessarily required. 

In a similar experiment Aberhart et al. (218) fed DL-cystines chirally labelled at carbon-3 with tritium to P. chrysogenum in combination with C-cystine and found that with the (3R) compound 76% of the tritium label was retained whereas with the (3iS) compound only 21% of the label was retained. 

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